The association between frequency of e-cigarette use and long-term smoking cessation outcomes among treatment-seeking smokers receiving a behavioral intervention.

Abstract

A growing body of literature suggests daily, but not non-daily, e-cigarette use is associated with greater odds of quitting combustible cigarettes in the general adult population. However, it is unknown if these findings generalize to treatment-seeking smokers who are receiving a behavioral intervention. Our primary aim was to examine whether frequency of e-cigarette use was associated with subsequent cessation among treatment-seeking smokers who are receiving a behavioral smoking cessation intervention. Participants (N = 2637) enrolled in a RCT of web-based smoking treatments reported their use of e-cigarettes at baseline, 3-, and 6-months. Three groups were created based on e-cigarette use: (1) non-users, (2) intermittent users, and (3) daily users. The primary outcome was complete-case, self-reported 30-day point prevalence abstinence at 12 months. Compared to non-users, daily e-cigarette users were significantly less likely to be abstinent (21.39 % vs. 29.68 %; p = .006). Quit rates for intermittent users (24.56 %) were not significantly different from non-users (p = .092). Nicotine dependence moderated the results such that among smokers with low nicotine dependence, those who used e-cigarettes (intermittently or daily) were less likely to quit than non-users; these differences were not significant among those with high nicotine dependence. Post hoc analyses indicated that initiating daily e-cigarette use after baseline, but not daily e-cigarette use at baseline, was associated with lower odds of cessation. Daily e-cig use may be associated with lower odds of quitting smoking among treatment-seeking smokers, particularly among those with lower nicotine dependence and who initiate daily use after beginning an intervention.